EFFECT OF CONTINUOUS-WAVE ULTRASOUND ON BLOOD FLOW IN SKELETAL-MUSCLE

Background and Purpose. The purpose of this study was to determine the effect of ultrasound on forearm, skin, and muscle blood flow. Subjects. Twenty volunteers without known vascular problems (10 male, 10 female) participated. Methods. All subjects received a treatment of continuous-wave ultrasound to the anterior forearm at a dosage of 1.5 W/cm(2) for a duration of 5 minutes. The contralateral forearm served as the control and received identical treatment, except the ultrasound output remained at zero. Forearm blood flow was measured using venous occlusion plethysmography, and skin blood flow was measured using cutaneous laser-Doppler flowmetry before and after ultrasound administration, with the difference being muscle blood flow. Results. No differences between the control arm and the ultrasound-treated arm were found for muscle, skin, and forearm blood flow. Conclusion and Discussion. These results suggest that administration of continuous-wave ultrasound at the prescribed dosage had no effect on skeletal muscle blood flow for up to 30 minutes posttreatment. Thus, muscle hyperemia is probably not the primary mechansim responsible for the clinical benefits seen following the use of ultrasound as a therapeutic modality.